So, some questions: Should one always practice playing accurately? Can one acquire the desired speed(with control) be by just playing really fast(with less control)?
Greetings.The reason for why your friend may be able to play fast is because there are much less facets to the property of touch. There is much less resistance and for what may be fast on a keyboard will not be hold true on an acoustic or weighted keys. I would say that to learn the basics on a keyboard is okay, but you cannot aquire a proper technique. Of course it is easier to play certain techniques, but that will not work on weighted keyes. In fact it will be harder to play correctly, because of the already learned technique. As for learning the notes and the beginning material, there is nothing wrong with a keyboard. However there is no way one could aquire a proper technique by practicing on a keyboard. As I said it is very dangerous to aquire improper technique for it is difficult to relearn in correctly. As for the speed, it is easier in my opinion to play faster on a keyboard due to the very light touch, but you won't have that speed playing on a real piano unless you practice on a real piano, or weighted keyes. Hope this helps.